Portable refrigerant recovery units or carts are used in connection with the service and maintenance of refrigeration systems including an automotive vehicle's air conditioning system. The refrigerant recovery unit connects to the air conditioning system of the automotive vehicle to recover refrigerant out of the system, separate out oil and contaminants, and recharge the system with additional refrigerant.
An oil inject portion of the refrigerant recovery unit is used to put the same amount of compressor oil back into the air conditioning system as was taken out during the recovery process. This may be a visual determination by reading a graduation on the oil drain bottle and on the oil inject bottle, or it may be an automated process.
The oil required in the air conditioning system of a conventional automotive vehicle typically differs from the oil required in a hybrid vehicle. Conventional automotive air conditioning systems typically use polyalkylene glycol lubricant (“PAG”) oil as the refrigerant lubricant or compressor oil, whereas many hybrid vehicle systems use polyolester (“POE”) oil. These oils are generally not compatible with each other. Thus, there is a need to ensure that these various types of oil do not mix with each other between recovery processes.
Portable refrigerant recovery units or carts used in connection with the service and maintenance of refrigeration systems often have vacuum pumps to create a vacuum in order to draw refrigerant from a vehicle's air conditioning system. The vacuum pump itself may be lubricated with lubricating oil. The lubricating oil may need to be changed from time to time.
Common vacuum pumps have an oil drain plug that is removed in order to drain the vacuum pump oil. Then the person performing the oil change locates a container to drain the oil into. On some pieces of air conditioning servicing equipment, there is no place to set the container so a person must hold the container while the oil is draining. Having a person hold the oil container can lead to spills related to human err and require the time of the holder. A system that automates the oil draining process may be desired.